B58 Ignition Coil Conversion

From MS4X Wiki

Like every other part in and on your engine the ignition coils got on in years and wear out over time. Meanwhile, ignition coil technology moved on and coils got stronger, more robust and more efficient.

So why not take the chance and upgrade to the latest generation of ignition coils introduced by BMW and Eldor with the B58 and S58 engines.

Compared to aftermarket solutions (for example with blue or red caps) these coils undergo excessive testing and quality controlling because they are used in countless engines. That has two very significant advantages, the B58 igniton coils are readily available all over the world, and dirt cheap compared to aftermarket solutions.

Also it doesn't need desoldering of the ignition coil drivers (IGBTs) from your ECU like the VAG / R8 ignition coil conversion.

Note: This conversion though is mainly intended for M52TU and M54 engines that still have the old style ignition coils that are bolted to the valve cover (BMW 11121432928).

For those who have the newer plug-in style ignition coils, it will be cheaper with just replacing replacing them with the latest revision made by Eldor (BMW 12138657273).

But in any case you can upgrade to B58/S58 hardware, you will have to change the valve cover though.


Parts list:

  • 6x BMW B58 or S58 from Eldor (BMW 12138643360)
  • 6x TE MCON 1.2 sealed connector housing (TE 1-1718644-1)
  • 18x TE MCON 1.2 sealed pin for 1.0mm² - 1.5mm² wire (TE 7-1452671-3)

If you want to be on the safe side, you can get yourself another spare ignition coil wiring harness where you perform the modification.

Hint: M52TU, M54 old style, M54 pencil coil and M56 engines all have different ignition coil wiring harnesses, so buy according to your engine.

For esthetic reasons, you ideally buy one from M54 engine with pencil coils because the rubber sealing of the wires will slide over the new connectors making it look better. In most cases that needs modification of the connector on the car side though.

Wiring Modification

ECU Modification

B58 Dwell Times.png

To achive the best performance out of this mod without overheating the coils you have to adjust the dwell times.

Following dwell times where calculated from the B58B30 calibration values. Don't forget to adjust the multispark table.

Depending on your engine you need to copy these values to the bolt-in ignition coil tables (_300) or the pencil style ignition coil tables (_pc).

B58 Coil Dwell Times for MS42 & MS43
V ms
0.0 12.901
6.0 9.899
8.0 5.952
10.0 4.448
12.0 3.648
14.0 3.152
16.0 2.651
25.0 2.501
V ms
0.0 3.872
6.0 2.971
8.0 2.139
10.0 1.691
12.0 1.221
14.0 0.901
16.0 0.795
25.0 0.000